Corny keg

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Mangold
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Corny keg

Post by Mangold » Sat Jan 25, 2020 10:42 am

Hi all. Long time since I posted, and I can't access my old account which was under the user name Manngold (double N). Been a while since I kegged, two to three years. Can someone help me out with what I need to be successful. I have corny kegs but can't remember what else I need.

My plan is to deep clean / strip clean the keg. Re order some new seals. Should I get new disconnects?

Also what size and length beer line is suggested. I have the ability to chill the keg, but for the most part it will be sat in a shed.

I have a brand new gas cansiter. When it comes to force carbing can someone point me in the right direction for psi for a 5.5% Pale (it is a copy of the Seirrea Nevada Pale Ale) and a temp I should carb at?

Thanks all. Glad to be back brewing.

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Kev888
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Re: Corny keg

Post by Kev888 » Sat Jan 25, 2020 11:10 am

Hello, and welcome back!

The disconnects shouldn't need replacing unless their inside surface is scratched or their inner poppet perished. They can be taken apart for cleaning though (at least the plastic ones can, I've not had the more recent metal ones yet).

Your questions about force carbonating and line length depend very much on pressure but also (unfortunately) temperature, since the two are directly related. So if you can't regulate the temperature then the pressure will need to be varied to compensate. I would suggest connecting up the gas only when needed and set to a pressure suitable for the temperature (of the beer) at that time.

There are various charts that can help choose the pressure needed for a given temperature and equilibrium of carbonation, such as this one:
force carbonation chart.jpg
But they tend to suggest volumes of CO2 that are too high for British styles and tastes, so go for the low end of what the chart recommends unless you're making an american style or similar.

For serving, if you only want to carbonate to very low levels then you can get away without doing things properly; just a short bit of line can work. But if you want higher levels of carbonation, as of course many styles do, then there does need to be decent back-pressure to balance or it will foam. It isn't very practical to balance with 3/8" beer line - due to the lengths needed (and the online calculators for that tend to under-estimate by a long way). So I would suggest stepping down to 3/16" line and/or especially in your case (where things will vary) getting a decent flow control if you haven't already; both work similarly, adding to the restriction and slowing the flow. Flow controls can be got built into corny disconnects these days, which is a neat solution. Or inline versions (with a red collar) can have 3/8" in and 3/16" out so double as a reducer.
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Re: Corny keg

Post by vacant » Sat Jan 25, 2020 1:30 pm

Mangold wrote:
Sat Jan 25, 2020 10:42 am
Re order some new seals.
All the kegs I bought cheap in 2015 were "refurbished" but didn't look like they had new seals. They would all seal by emptying a kettle of boiling water in and closing (I could then press down on the outlet covered by a cloth to get hot water spurting through the dip tube). I bought some new O rings but just kept them as spares.
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Re: Corny keg

Post by Mangold » Sat Jan 25, 2020 2:07 pm

Vacant and kev, thanks for the response from the both of you. Sorry, but could you dumb it down a bit for me kev. I have always struggled with my keg set up but would like to get it right.

To clarify, I can control the temp of keg when carbing it. In the past I used the method of adding co2, and rocking it for a minute or so, but always found that I would be over carbing it.

I have flow control taps, I have one flow control that I can attach directly onto a keg via a disconnect, and two others that need beer line. I suspect that in the past my beer line was too wide (I want to say 3/16 but this is a pure guess). Should I get the smallest beer line possible (not length but diameter(is this even the right term)).

If I can control temp and pressure, how long should I carb a pale for? I am guessing aim for something in the yellow?

Does the length of gas line play any factor?

As you can tell my knowledge of science and pressure isn't great. I am a Sociology teacher and not a physicist lol.

Thanks for the welcome back.

Already planning my next brew, Dennis Kings Galaxy Delight!

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Kev888
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Re: Corny keg

Post by Kev888 » Sat Jan 25, 2020 11:54 pm

The first thing is to decide how carbonated you want the particular beer to be, this is typically referred to in 'volumes of CO2' as contained within the body of that chart. You can use formulas to work out the priming sugar needed to achieve that, or else you can force carbonate.

If you force carbonate then I would suggest avoiding the rapid methods (of highly pressurising the beer for a short time) unless you are in a hurry; it is harder to judge accurately and if you leave it too long then it will become over-carbonated. Instead I would go for setting the 'equilibrium' combo of pressure and temperature as described in that chart - set the pressure needed for the temperature that the beer is at. This method can take several days or more to finish carbonating the beer (reaching said equilibrium) but it will not overshoot.

To keep things simple I would suggest also serving at the same pressure/temperature combo as the beer was carbonated for. This means the carbonation will not change whilst serving (changes can manifest themselves as foaming when serving). This is the pressure that your beer line and/or flow controls should be set up to suit.

The idea is to have enough restriction in the beer line to counter the pressure in question and cause a slow pour; as slow as your patience will allow really. You can simply use long lengths of beer line to do this, but 3/8" line (standard for cornys, roughly 10mm outside diameter) isn't very restrictive and it would take dozens of meters. So 3/16" line is much more suitable, and also much more flexible; depending on the pressure you might want to start with say four meters and slowly reduce the length until the pour rate is adequate. The line is reasonably cheap in longer lengths, so get enough to experiment with initially.

Alternatively you can use flow controls to add the restriction. Some taps have this built in, though the range of adjustment may not be enough on some - in which case team with 3/16" line. My personal favourite is to use an inline flow control before a couple meters of 3/16" line but your preferences or circumstances may well be different.

There are other ways so there is not one definitive answer, but for me this is the most reliable approach. Or as mentioned previously you can use very low levels of carbonation, which would be under-carbonated for some styles, as there is far less problem with foaming then. Personally I prefer to choose my beer characteristics and get the lines to suit, rather than have the beer dictated by a poor serving setup. But if things get awkward a small compromise between the two might help; i.e. go for the lowest carbonation level that you are happy with for the style.
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Re: Corny keg

Post by IPA » Sun Jan 26, 2020 9:25 am

Line length counts for nothing. I use 60 cm of 7 mm tube. I even have one cornie fitted with a tap direct onto the post. It is important to use taps with a flow control.
Ignore all of those American carbonation charts they only work,sometimes, with bottled beer.
If you want to serve commercial quality bright beer this is how to do it.
First of all change the out dip tube with a float take off. Either a Latstock or a Fermentasaurus. I have both and find that the Latstock is the best.
Ferment your beer to its final gravity then fine it with gelatine . Three days later transfer it to another vessel and prime it with 2.5 g a litre of household white sugar disolved in hot water and gently stirred in.
Fill your cornies and seal the lid with gas at one bar. You will know the lid is sealed when gas stops flowing.
Leave to condition for at least 14 days. It helps if you use a spunding valve to regulate the internal pressure to 0.5 bar before connecting your tap.
One more tip. Fill a 50 cl plastic bottle with beer when you keg. A simple squeeze test over the next few days will let you know how carbonation is progressing.
If the beer foams when serving the only reason is over carbonation not the line length.
DO NOT USE THOSE CARBONATION CALCULATORS.
Also there is no good reason to force carbonate unless you are making lemonade.
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Re: Corny keg

Post by Kev888 » Sun Jan 26, 2020 11:53 am

Well..
There is nothing mysterious about line length, it does exactly the same as a flow control; they both cause restriction. So if a flow control works then so will a long narrow line (it just cannot work for one and not the other); both are valid methods. If you have found line lengths count for nothing then your line cannot have been nearly narrow (or long) enough to have an obvious effect. Which isn't a criticism; the line-length calculators and formulas around generally give very poor advice for the kinds of pressures and lines typically used for serving British style home brew - I think they incorrectly assume that things scale linearly, certainly they always suggest 'far' too little line to work well in most of our situations.

The american charts (and calculators) actually work fine for gauging the equilibrium pressure and temperature, regardless of packaging method; they're just objective values, and the laws of physics aren't different over the pond. Where they fall down is the subjective advice for what volumes to choose (i.e. the coloured bands) - which are generally too high for British tastes and styles. Happily it doesn't take much brain power to simply choose a lower level, I'd suggest the lower end of any range they advise might be the upper end of what we should aim for, unless actually making a US style of course.

Being over carbonated (or at least more carbonated than realised) is certainly a very common reason for foaming but is far from being the only one; unfortunately it isn't that simplistic. Inadequate flow restriction for the pressure, serving at too low a pressure for the carbonation present, and having poor joins and sharp bends in the line can (and do) all encourage foaming when serving. It is entirely viable to balance any normal level of carbonation, if done properly; nastily fizzy lagers at least serve to demonstrate that, if nothing else.

There are advantages and disadvantages to both force carbonating and naturally carbonating; a different viewpoint might equally say there was no good reason to naturally carbonate (and I wouldn't agree with that either). Personally I use both methods, according to my preference at the time - it isn't necessary to make over-carbonated muck with either method, just as the use of a keg does not dictate bland fizzy pap. There are those who believe otherwise or that there is only one way to do things, but of course kegs and gas are just tools, the rest is down to how the brewer actually uses them.
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Re: Corny keg

Post by IPA » Sun Jan 26, 2020 4:57 pm

Hi Kev
We obviously have different views on this subject. But please try this. Fill a keg with uncarbonated water and you will not be able to make it foam on exiting the tap.No matter what the serving pressure or the line length..As my maths master made us print at the end of a mathmatical proof
QED (QUAD ERRAT DEMONSTRANDUM) "That which had to be proved has been proved"

It's another one of those internet myths such as oxygen can permeate a pressurised PET bottle. Sure it can permeate an unpressurised bottle but not one under internal pressure higher than atmospheric pressure.
Last edited by IPA on Sun Jan 26, 2020 5:06 pm, edited 2 times in total.
"You're not drunk if you can lie on the floor without holding on." Dean Martin

1. Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in sideways, thoroughly used, totally worn out and loudly proclaiming... "f*ck, what a trip

It's better to lose time with friends than to lose friends with time (Portuguese proverb)

Alone we travel faster
Together we travel further
( In an admonishing email from our golf club)

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Re: Corny keg

Post by IPA » Sun Jan 26, 2020 4:58 pm

IPA wrote:
Sun Jan 26, 2020 4:57 pm
Sorry double post
Last edited by IPA on Sun Jan 26, 2020 5:01 pm, edited 1 time in total.
"You're not drunk if you can lie on the floor without holding on." Dean Martin

1. Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in sideways, thoroughly used, totally worn out and loudly proclaiming... "f*ck, what a trip

It's better to lose time with friends than to lose friends with time (Portuguese proverb)

Alone we travel faster
Together we travel further
( In an admonishing email from our golf club)

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Re: Corny keg

Post by IPA » Sun Jan 26, 2020 4:59 pm

Sorry double post
"You're not drunk if you can lie on the floor without holding on." Dean Martin

1. Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in sideways, thoroughly used, totally worn out and loudly proclaiming... "f*ck, what a trip

It's better to lose time with friends than to lose friends with time (Portuguese proverb)

Alone we travel faster
Together we travel further
( In an admonishing email from our golf club)

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Kev888
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Re: Corny keg

Post by Kev888 » Sun Jan 26, 2020 6:16 pm

Yes we do disagree (to some extent anyway) on these kinds of subjects, but of course that isn't unusual on a homebrew forum! In case it isn't already clear, it is nothing at all personal; there is a great deal you say that I do agree with and appreciate your contributions to homebrewing.

Anyway, I agree that uncarbonated water will not foam, in the way we mean it (though it can be made to bubble). But whilst I never champion highly carbonated beer, I do like it to be appropriate for the style in question so there will always be 'some' carbonation in it even for British styles, and for some foreign styles quite a bit. Additionally I like the beer to have decent head retention which (as a side effect) causes any bubbles in the line to persist stubbornly as foam. So whilst I could brew beer with somewhat more water-like characteristics to make serving easier, my own personal preference is to have the beer as wished and adjust the serving setup instead. It isn't actually very difficult unless things are out of control, such as temperature or the initial levels of carbonation; that usually is what trips people up and your spunding valve suggestion could be very useful in avoiding the latter.

PET isn't very permeable so it would take years to have significant effect (with some other plastics much less time) and it sounds like you understand oxygen will mix with unpressurised CO2 so we don't need to dispel the semi-myth of the CO2 blanket. But unfortunately pressurising the CO2 to carbonation levels doesn't really make very much difference, little has changed that affects the way such gasses behave. Unlike dense liquids which tend to fit people's mental models better, gasses such as these really don't impede each other very much; they're able to act relatively independently of each other in some respects - so each gas is free to establish equal levels of itself both sides of any permeable wall, due to its own differential in pressure. In our case CO2 leaks out because of the differential in CO2 pressure, and oxygen leaks in because of the differential in oxygen pressure - at a hopefully 'very' slow rate determined by how easily they can get through the container wall. Eventually both CO2 and oxygen will be at the same levels inside and outside, i.e. not just the total pressure but also the partial pressures of the individual gasses.

That latter is going off topic a bit for this thread, but if you want to learn more about gas's wierd behaviour, look up (Dalton's) law of partial pressures in combo with the other gas laws. Homebrewers may be a bit vague about such things, but they're quite well understood by science.
Last edited by Kev888 on Wed Feb 05, 2020 1:31 pm, edited 1 time in total.
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Re: Corny keg

Post by Jocky » Sun Jan 26, 2020 7:36 pm

I'm with Kev on this one.

I like quite a few styles that are traditionally higher carbonated (Weissbier and various Belgians). I have also had the misfortune to have these at a pub where they evidently had a leak in their system and as a result I had bother a Schneider Weisse Hopfenweisse and a Karmeliet Tripel that were woefully undercarbonated and as a result insipidly undrinkable.
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Re: Corny keg

Post by Jocky » Sun Jan 26, 2020 7:55 pm

I recently got into corny kegs and there's a couple of things I'd like to share:

1. This is a really good carbonation chart: https://jollygoodbeer.co.uk/wp-content/ ... or_CO2.pdf

2. If you're in the UK then ignore US line length balancing calculators unless they allow you to specify the internal diameter of beer line you are using. The reason for this is that the US seems to refer to beer line sizes based upon the internal diameter, whereas in the UK it's referred to by the external diameter.
What that means is that UK line is more restrictive and you can use a shorter length than US based line calculations will give you.

Personally I've found that 5-6 feet of 3/16" external diameter will pour even highly carbonated beers happily. I've dispensed beer at 20PSI with this.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

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Re: Corny keg

Post by Mangold » Sun Jan 26, 2020 8:36 pm

Thanks all.

I think I will do the following.

Carb with sugar as I have done previously but use gas to seal.yhe keg. About 2.5 to 3g per litre.

Carb for two weeks in doors or at 18c in the temp control fridge.

Get some 3/16 line (does this fit on regular disconnect or do I need some additional john guest fitting?).

Purchase one of these.... http://www.homebrewkent.co.uk/product/l ... eer-float/

But from the bay.

Use my flow control taps.

I do have a spunding valve, should I bother with it?

Thanks all for the response. Truth be told, and I am not ungrateful, I just don't get a lot of it. So am trying to take a building block approach more than anything else.

If anyone has any other tips or sees any problems with what I have said please do let me know.

Time to enjoy a pint (shop bought...boo!)

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Re: Corny keg

Post by Jocky » Sun Jan 26, 2020 9:56 pm

3/16” line you’ll need a reducer for.

You can either get an in-line reducer if you are using barbed disconnects, or if you have screw fitting disconnects with a FFL fitting you can get a stem reducer which reduces the FFL fitting to 3/16”.

Spunding valves are useful for natural carbonation in a keg. Using the pressure chart I linked above you can figure out what pressure to set it at. A week at 18c should be plenty of time. One thing to note is that when you pressure seal the corny initially if you disconnect the gas pressure the CO2 you have put in will absorb into the liquid over a few hours and you might need to top it up.

I will say you don’t need a float, I have naturally carbed in a keg and then blown out the yeast created in the first couple of pours, but the float avoids this problem entirely.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

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